Floatless carburetor



March 31, 1964 J. o. SARTO FLOATLESS CARBURETOR 2 Sheets-Sheet 1 Filed March 23, 1959 \w w x f, 2 1 M 4 MW 3. M Cw/A I .3 5 w; 9 A HHHH. w M W M a INVENTOR. c/ORMH 0. Q5145 T0. f/M MM March 31, 1964 J. o. SARTO 3,127,453

FLOATLESS CARBURETOR Filed March 23, 1959 2 Sheets-Sheet 2 .90 IN VEN TOR.

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United States Patent Ofiice 3,127,453 Fatented Mar. 31, 1964 3,127,453 FLQA'ILEfiS QAREURETGR Jorma 0. Sarto, Orchard Lake, Mich assignor to Ehrysler Corporation, Highland Park, Mich, a corporation of Delaware Filed Mar. 23, 1959, Ser. No. $91,228 14 Claims. ((31. 261-36) This invention relates to floatless carburetors for automotive vehicles and in particular to the type having overflow means for maintaining a constant fuel bowl level and also having a fuel recirculating unit for constantly supplying an excess of fuel to the fuel bowl.

One of the main advantages obtained by using floatless carburetors is the absence of float and valve parts which may wear and allow an incorrect amount of fuel to flow into the bowl which will result in a non-constant fuel head in the bowl and undesirable fuel mixtures. Moreover, the float type carburetor is susceptible to undesirable variations of the fuel level in its fuel bowl caused by travel over rough roads or stop and go driving which causes the fuel in the bowl to move back and forth and bounce the carburetor float. Other disadvantages of the float type carburetor are that the inlet orifice to the bowl may be held open by dirt and cause a flooding condition to exist particularly during idle and cranking; the carburetor must have a size sufficient to accommodate the float; the needle valve controlling the delivery of fuel to the bowl may leak to allow residual pressure in the fuel pump to supply fuel to the carburetor after the en ine is shut off so that at hot start the combustion mixture will be over enriched; each carburetor employed must have its own float; and relatively small fuel conduits in the float type carburetor frequently lead to vapor lock conditions therein.

It is a major object of this invention to provide a floatless type carburetor with a recirculating type of fuel control unit to obviate the above mentioned disadvantages of the float type carburetor.

A further object is to provide a floatless type carburetor having return flow conduit means with a fuel flow control unit which is responsive to return flow fuel pressure to thereby regulate the volume of fuel flowing into the heat bowl.

Another object is to provide a fioatless type carburetor with a vacuum responsive device for regulating the recirculating fuel flow according to vacuum within the intake air passage of the carburetor.

Further objects and advantages will become apparent from the following description and drawings, in which:

FIGURE 1 represents a cross sectional view of a floatless type carburetor embodying applicants overflow recirculating fuel system; and

FIGURE 2 represents a variation in the fuel recirculating unit of the system of FIGURE 1.

Referring to FIGURE 1, a carburetor generally designated 16 is provided with an air intake passage 12 having a choke blade 14 and a throttle blade 16 pivotally mounted therein in the conventional manner. A conventional primary venturi 18 extends into the passage 12; and communicates with the fuel bowl 20 through primary restriction 22. Fuel bowl 2%) communicates with a fuel source through carburetor feed conduit 24. An overflow port 39 formed by wall 31 allows a level designated as A of fuel to remain in the fuel bowl. Wall 31 may extend across the entire length of the carburetor to accommodate any quantity of excess fuel overflow.

The fuel recirculator control unit designated 58 is provided with a vacuum pressure chamber 6% which communicates with the main air intake passage 12 of the carburetor adjacent throttle blade 16 through a vacuum line 62. A pressure responsive diaphragm 64 comprises a movable wall to complete chamber 6%). An overflow chamber as is provided on the other side of diaphragm 64 and communicates through return flow line 68 with verilow port 3%). An overflow chamber outlet orifice 74 connects chamber 66 with the inlet 72 of a constant pressure variable stroke fuel pump 74. Inlet 72 of pump 74 is also operatively connected to a fuel tank 76 by a feed line 78 and a pump inlet orifice 8t). Carburetor feed conduit 24 operatively connected to the output end of pump 74 is provided with a feed control orifice 82 which is conveniently placed within overflow chamber 65% so that a single valve actuating means or stem 84 could be operatively connected to diaphragm 64 and be provided with needle valves 86, 88, and fit to respectively control the flow through orifices 82, 7b, and 30 respectively in response to the return flow head or pressure in line 68 and the vacuum within passage 12 of the carburetor. Thus the valves 85, 8d and 9% may be called the feed control valve, return valve, and inlet valve means respectively.

In the operation of the device of FIGURE 1, fuel is delivered by pump 74 through carburetor feed conduit .24- in excess of the requirements of the engine. This excess flows over wall 31 into the overflow port 30 and through line 63 into overflow chamber 66. As chamber 65 fills it exerts a pressure on diaphragm 54 tending to restrict orifice 82 and orifice 85) by the action of valves 36 and 9% respectively. Simultaneously with the restriction of these orifices, orifice '79 is open to allow fuel in chamber 66 to pass through to the inlet 72 of pump 74- to thereby recirculate the return flow fuel back through the carburetor feed conduit 24. Orifice 80 and valve are of such a shape as to be able to completely close while orifice 82 is still partially opened to allow a recirculation of the fuel even though no new fuel is obtained from the fuel tank 76. Thus valve 99 is also a movement limiting stop for actuator 84. A spring 61 in chamber as constantly urges diaphragm 64 to a position which tends to open orifices 82 and 80. The force of this spring, however, is of such magnitude as to be overcome by the vacuum in air passage 12 during the time that the throttle blade 16 is closed as shown in the drawing. This closed throttle position signifies low fuel requirements and consequently causes diaphragm 64 to be urged in a direction tending to restrict the flow of fuel from tank 76 while allowing an increase in recirculation of overflow fuel through orifice 70 and into pump 74. In the above regard, the pressure at the region of opening of line 6?. into passage 12 will increase or decrease as throttle it; opens or closes respectively to increase or decrease the air flow in passage 12 respectively.

The presence of all of the valves 86, 88, and 90 results in more stabilized operating efficiency of the automobile than would be possible by omitting any one of them. For example, valve 86 in useful in trimming down the flow of fuel to the bowl 20 during engine idle to prevent the excess flow volume from becoming too great for the return conduit 68 to accommodate and causing an undesirable flow through orifice 18. Valve 90 is useful in preventing pressure variations in line 78 caused by the motion of the fuel therein from affecting the pressure of pump 74-. Valve 88 is useful for preventing pump 74 from pumping air when the fuel requirements of the engine are high and the overflow rate is low. It is obvious, however, that under certain engine operating conditions and in certain engine uses one or more of these valves may be omitted.

Referring to FIGURE 2 wherein structures identical to that of FIGURE 1 are similarly designated, the carburetor 10 is provided with a variation of the fuel recirculating control unit of FIGURE 1 and is designated as 2. This unit comprises a pump outlet orifice 93 and outlet valve 94 having fuel passage slots 95 therein. This valve 94 has a stem 97 which slides freely in aperture 9 and operatively abuts a valve operating arm 96 secured to a valve control float 93 which float is pivotally mounted at 1%)!) in overflow chamber 102 of the unit. The overflow return valve 88 and the pump inlet valve 90 are connected through a single shaft 91 pivotally secured to the float 98 at 101 to move up and down therewith. An acceleration booster unit comprising a cylinder 104 and a piston 1% slidably mounted therein has connected thereto a shaft 108. The piston 1% and shaft 1% comprise float biasing means adapted to abut the top of float 93 and urge it downwardly as the pressure in inlet passage 12' adjacent vacuum line 62 increases by the opening of throttle blade 16. Conversely, piston 1% will be urged upwardly away from float 9'8 to allow the float to move upwardly and restrict pump inlet orifice 80 as the pressure in passage 12 adjacent to the outlet of vacuum line 62 decreases by the closing of throttle blade 16. It is noted that inlet orifice 80 at low fuel consumption conditions will become completely restricted and prevent complete restriction of outlet orifice 93 to allow proper fuel supply to the fuel bowl. It is also noted that the flow area of aperture 99 is not large enough to significantly affect the return fuel pressure in chamber 102.

In the operation of the recirculating flow unit of FIG- URE 2, the action of the float is substantially the same as that of diaphragm 64 and its upward movement in response to a filling of overflow chamber 102 will result in an opening of the overflow return orifice 7b to allow a greater portion of the fuel to recirculate and at the same time causing a restriction of pump inlet orifice 8th to restrict the amount of fuel obtained from the fuel tank 76.

The specific shapes and arrangement of the feed control units 58 and 92 as shown in the drawings represent convenient structure but it is not intended that these units be limited to these shapes. Obvious modifications in design and arrangement could be made by those skilled in the art.

I claim:

1. In a carburetor, an air intake passage, a fuel orifice opening into said passage, a fuel bowl connected to said orifice and having overflow means, a fuel supply, a feed conduit connecting said supply and bowl, pump means in said conduit for supplying said bowl with an excess of fuel from said supply, an overflow chamber having an inlet in communication with said overflow means to receive excess fuel therefrom and having an outlet in communication with the inlet side of said pump means, return valve means in said outlet for adjusting the flow of said excess fuel to said pump means, feed control valve means in said feed conduit downstream of said pump means for adjusting the flow of fuel to said bowl, shiftable valve actuating means responsive to the fuel in said overflow chamber for shifting in one direction or the opposite as the fuel in said chamber increases or decreases respectively, means operatively connecting said actuating means with each of said valve means for progressively opening said return valve means and closing said feed control valve means in unison upon movement of said actuating means in said one direction and for progressively closing said return valve means and opening said feed control valve means in unison upon movement of said actuating means in the opposite direction.

2. In the combination according to claim 1, said valve actuating means including a float in said overflow chamber movable in said one direction or the opposite as the fuel level in said chamber rises or falls respectively, biasing means yieldingly urging said float in said opposite direction, means for increasing the air pressure in a region of said air intake passage as the rate of air flow therethrough increases, and means responsive to the pressure at said region for opposing said biasing means with decreasing force as the pressure at said region increases,

4 thereby to enable said biasing means to accelerate the opening of said feed control valve means upon acceleration of the rate of said air flow.

3. In the combination according to claim 1, inlet valve means in said feed conduit at the inlet side of said pump means in parallelism with said return valve means for adjusting the flow of fuel from said supply to said pumping means, said actuating means being also operatively connected with said inlet valve means for progressively opening and closing the latter with opening and closing respectively of said feed control valve means.

4. In the combination according to claim 3, said inlet valve means being arranged to close before said feed cor trol valve means is completely closed and comprising a movement limiting stop for said valve actuating means to prevent complete closing of the latter valve.

5. In the combination according to claim 4, said valve actuating means including a float in said overflow chamber movable in said one direction or the opposite as the fuel level in said chamber rises or falls respectively, biasing means yielding urging said float in said opposite direction, means for increasing the air pressure in a region of said air intake passage as the rate of air flow therethrough increases, and means responsive to the pressure at said region for opposing said biasing means with decreasing force as the pressure at said region increases, thereby to enable said biasing means to accelerate the opening of said feed control and inlet valve means upon acceleration of the rate of said air flow.

6. In a carburetor, an air intake passage, a fuel orifice opening into said passage, a fuel bowl connected to said orifice and having overflow means, a fuel supply, a feed conduit connecting said supply and bowl, pump means in said conduit for supplying said bowl with an excess of fuel from said supply, an overflow chamber having an inlet in communication with said overflow means to receive excess fuel therefrom and having an outlet in communication with the inlet side of said pump means, return valve means in said outlet for adjusting the flow of said excess fuel therethrough to said pump means, feed control valve means in said feed conduit downstream of said pumping means for adjusting the flow of fuel to said bowl, inlet valve means in said feed conduit at the inlet side of said pump means in parallelism with said return valve means for adjusting the flow of fuel from said supply to said pumping means, shiftable valve actuating means responsive to the pressure in said overflow chamber for shifting in one direction or the opposite with increasing or decreasing pressure respectively, means operatively connecting said actuating means with each of said valve means for progressively opening said return valve means and closing said feed control and inlet valve means in unison upon movement of said actuating means in said one direction and for progressively closing said return valve means and opening said feed control and inlet valve means in unison upon movement of said actuating means in the opposite direction, and biasing means yieldingly urging said actuating means in said opposite direction.

7. In the combination according to claim 6, means for increasing the air pressure in a region of said an intake passage as the rate of air flow therethrough increases, said actuating means including a movable wall of said chamber having one side exposed to the pressure in said chamber for shifting said actuating means in said one direction with increasing pressure and having its opposite side exposed to the pressure at said region of said air intake passage for shifting said actuating means in said opposite direction with increasing pressure at said region, thereby to accelerate the opening of said feed control and inlet valve means upon acceleration of the rate of said air flow.

8. In the combination according to claim 6, said inlet valve means comprising movement limiting means at its closed position effective t stop continued movement of said actuating means in said one direction, and said feed control valve means being partially open when said inlet valve means is at said closed position.

9. In the combination according to claim 8, means for increasing the air pressure in a region of said air intake passage as the rate of air flow therethrough increases, said actuating means including a movable Wall of said chamber having one side exposed to the pressure in said chamber for shifting said actuating means in said one direction with increasing pressure and having its opposite side exposed to the pressure at said region of said air intake passage for shifting said actuating means in said opposite direction with increasing pressure at said region, thereby to accelerate the opening of said feed control and inlet valve means upon acceleration of the rate of said air flow.

10. In a carburetor, an air intake passage means for increasing the air pressure in a region of said intake passage as the rate of airflow therethrough increases, a fuel orifice opening into said passage, a fuel bowl connected to said orifice and having overflow means, a fuel supply, a feed conduit connecting said supply and bowl, pump means in said conduit for supplying said bowl with an excess of fuel from said supply, an overflow return line connecting said overflow means with the inlet side of said pump means for recirculating said excess fuel, return valve means in said return line for adjusting the flow of said excess fuel to said pump means, feed control valve means in said feed conduit downstream of said pump means for adjusting the flow of fuel to said bowl, shiftable valve actuating means responsive to the air pressure at said region of said passage for shifting in one direction or the opposite with decreasing or increasing air pressure respectively, and means operatively connecting said actuating means with each of said valve means for progressively opening said return valve means and closing said feed control valve means in unison upon movement of said actuating means in said one direction and for progressively closing said return valve means and opening said feed control valve means in unison upon movement of said actuating means in said opposite direction.

11. In the combination according to claim 10, inlet valve means in said feed conduit at the inlet side of said pump means and in parallelism with said return valve means, said inlet valve means being also operatively connected with said valve actuator and being progressively opened and closed by actuation of the latter in unison with opening and closing respectively of said feed control valve.

12. In the combination according to claim 10, inlet valve means in said feed conduit at the inlet side of said pump means and in parallelism with said return valve means, said inlet valve means being also operatively connected with said valve actuator and being progressively opened and closed by actuation of the latter in unison with opening and closing respectively of said feed control valve, said inlet valve means being arranged to close before said feed control valve is completely closed and comprising movement limiting means for said actuator to prevent complete closing of the latter valve.

13. In a carburetor, an air intake passage, :1 fuel orifice opening into said passage, a fuel bowl connected to said orifice and having overflow means, a fuel supply, a feed conduit connecting said supply and bowl, pump means in said conduit for supplying said bowl with an excess of fuel from said supply, an overflow chamber having an inlet in communication with said overflow means to receive excess fuel therefrom and having an outlet in communication with the inlet side of said pump means, return valve means in said outlet for adjusting the flow of said excess fuel therethrough to said pump means, feed control valve means in said feed conduit downstream of said pump means for adjusting the flow of fuel to said bowl, shiftable valve actuating means responsive to the pressure in said overflow chamber for shifting in one direction or the opposite with increasing or decreasing pressure respectively, means operatively connecting said actuating means with each of said valve means for progressively opening said return valve means and closing said feed control valve means in unison upon movement of said actuating means in said one direction and for progressively closing said return valve means and opening said feed control valve means in unison upon movement of said actuating means in the opposite direction and biasing means yieldingly urging said actuating means in said opposite direction.

14. In the combination according to claim 13, means for increasing the air pressure in a region of said air intake passage as the rate of air flow therethrough increases, said actuating means including a movable wall of said chamber having one side exposed to the pressure in said chamber for shifting said actuating means in said one direction with increasing pressure and having its opposite side exposed to the pressure at said region of said air intake passage for shifting said actuating means in said opposite direction with increasing pressure at said region, thereby to accelerate the opening of said feed control valve means upon acceleration of the rate of said air flow.

References Cited in the file of this patent UNITED STATES PATENTS 1,148,922 Pagano Aug. 3, 1915 1,840,727 Linkert Jan. 12, 1932 1,909,390 Ball et al May 16, 1933 2,254,850 Mallory Sept. 2, 1941 2,409,965 Udale Oct. 22, 1946 2,454,974 Menneson Nov. 30, 1948 3,001,773 Johnson Sept. 26, 1961 FOREIGN PATENTS 608,211 Germany Jan. 18, 1935 

1. IN A CARBURETOR, AN AIR INTAKE PASSAGE, A FUEL ORIFICE OPENING INTO SAID PASSAGE, A FUEL BOWL CONNECTED TO SAID ORIFICE AND HAVING OVERFLOW MEANS, A FUEL SUPPLY, A FEED CONDUIT CONNECTING SAID SUPPLY AND BOWL, PUMP MEANS IN SAID CONDUIT FOR SUPPLYING SAID BOWL WITH AN EXCESS OF FUEL FROM SAID SUPPLY, AN OVERFLOW CHAMBER HAVING AN INLET IN COMMUNICATION WITH SAID OVERFLOW MEANS TO RECEIVE EXCESS FUEL THEREFROM AND HAVING AN OUTLET IN COMMUNICATION WITH THE INLET SIDE OF SAID PUMP MEANS, RETURN VALVE MEANS IN SAID OUTLET FOR ADJUSTING THE FLOW OF SAID EXCESS FUEL TO SAID PUMP MEANS, FEED CONTROL VALVE MEANS IN SAID FEED CONDUIT DOWNSTREAM OF SAID PUMP MEANS FOR ADJUSTING THE FLOW OF FUEL TO SAID BOWL, SHIFTABLE VALVE ACTUATING MEANS RESPONSIVE TO THE FUEL IN SAID OVERFLOW CHAMBER FOR SHIFTING IN ONE DIRECTION OR THE OPPOSITE AS THE FUEL IN SAID CHAMBER INCREASES OR DECREASES RESPECTIVELY, MEANS OPERATIVELY CONNECTING SAID ACTUATING MEANS WITH EACH OF SAID VALVE MEANS FOR PROGRESSIVELY OPENING SAID RETURN VALVE MEANS AND CLOSING SAID FEED CONTROL VALVE MEANS IN UNISON UPON MOVEMENT OF SAID ACTUATING MEANS IN SAID ONE DIRECTION AND FOR PROGRESSIVELY CLOSING SAID RETURN VALVE MEANS AND OPENING SAID FEED CONTROL VALVE MEANS IN UNISON UPON MOVEMENT OF SAID ACTUATING MEANS IN THE OPPOSITE DIRECTION. 